It is generally known to inlay or interlace yarns in selected wales of various types of flat warp knit fabrics. Such inlaid yarns have been incorporated in flat warp knit fabrics for ornamental purposes, to provide stiffness, and to provide other characteristics to the fabric. It is also known to form a circular warp knit cord or yarn on a small diameter circular knitting machine by forming wales of needle loops of base yarns circumferentially spaced around a circular warp knit tube, and with or without a core. Such a circular warp knit cord is disclosed in U.S. Pat. No. 4,123,830 in which the circular warp knit tube surrounds a centrally extending core. However, the circular warp knit tube of this patent does not include inlaid yarns interlaced in selected ones of the wales of the base yarn needle loops so that the longitudinal stretchability of the circular warp knit tube is not stabilized. Therefore, the cord of this patent is not suitable for use in certain operations, such as knitting, weaving, wrapping or the like, or for use in other instances where characteristics such as longitudinal stretchability, strength, stiffness, conductivity, bulk and filtration properties must be imparted to the warp knit cord.